1. Field of the Invention
The present invention relates to a sample extracting device and an adding device. In particular, the present invention relates to a valve which can be used as a sampling valve for extracting (sampling) a sample from a sample tank (a sample stock tank, a reaction adjusting tank, a stirring/mixing tank, or the like) used in chemical plants, industrial facilities, experiment facilities, or the like, or which can be used for adding an additive to a sample, and the present invention also relates to a sample extracting device and an adding device using this valve.
2. Description of the Related Art
FIG. 13 illustrates an example of a conventional sampling valve for sampling a sample from a sample tank.
The sample valve is structured such that a T-valve 202 which is formed in a substantial T-shape is provided at the bottom of a tank 200. By opening and closing the T-valve 202 by an actuator 204 or the like, a predetermined amount of the sample can be removed via a pipe 206.
However, in the sampling valve having the structure illustrated in FIG. 13, a liquid flow-out opening 208 of the pipe 206 is disposed lower than the solution surface of the sample in the tank 200. Thus, when the T-valve 202 is opened, the air remaining in the pipe passes through the pipe 206 and enters into the tank 200. If the sample is a liquid, the sample liquid becomes foamy due to the air, which may present problems in using the sample or the like.
Generally, with a sampling valve of this type of structure, it is desirable to appropriately clean the T-valve 202 and the pipe 206. However, when the sample in the tank 200 chemically changes or the state of the sample changes, the interior of the pipe cannot be cleaned quickly after sampling the sample. Thus, it is difficult to carry out sampling continuously in a state in which there are no impurities.
Further, in this sampling valve, structurally, cleaning of the interior of the pipe 206 is difficult, and it is easy for the cleaning liquid to remain in the pipe 206. An additional structure, such as a pipe for guiding the cleaning liquid within the pipe 206 or a valve for starting and stopping supply of the cleaning liquid, must be provided separately, such that the structure becomes complex on the whole, and the cost thereof increases.
FIG. 14 illustrates a conventional sampling valve 230 in which a movable element 234 provided between fixed elements 232, 236 is rotated so as to switch the sampling path, and a predetermined amount of a sample is sampled (see Japanese Patent Application Laid-Open (JP-A) No. 5-141549). With a specific sampling path selected, a corresponding valve 238 is opened and cleaning liquid is sucked in by a suction means 240 so as to be made to flow through and clean the sampling path.
However, in this sampling valve 230 as well, although the selected sampling path is cleaned, a pipette portion 242, whose distal end portion is disposed within the sample liquid, cannot be cleaned unless the sample tube containing the sample is removed. As a result, the sample cannot be sampled for checking changes in the properties over time.
FIG. 15 illustrates a conventional sampling valve 260 (see JP-A-6-241328) which is different than the above-described structures. This sampling valve 260 is provided with a nozzle 264 which forks off from a pipe 262. A predetermined amount of the fluid in the pipe 262 is extracted and used as a sample for testing or the like. The sample valve 260 has a ball valve structure such that even a minute amount of liquid does not remain in the valve at the time of opening and closing, and a circulating piece 265 can be cleaned.
However, as long as the continuously flowing sample exists in the pipe 262, the circulating piece 265 can be cleaned even at the sampling valve 260. However, if a portion of the sampled fluid already remains in the nozzle 264, the interior of the nozzle 264 is not cleaned, and thus, there is the possibility that impurities may remain.
In view of the aforementioned, an object of the present invention is to provide a valve which enables reliable cleaning of an interior of a sample tube, and a sample extracting and adding device using the valve.
A first aspect of the present invention is a device for extracting a sample from a container, the device comprising: (a) a cleaning tube; and (b) a sample tube having an opening, the sample tube being switchably mounted relative to the cleaning tube, between a sampling position at which the sample tube opening is placed in fluid communication with the environment for contacting a sample in a container, and a cleaning position at which the opening is placed in fluid communication with the cleaning tube for cleaning the sample tube.
The sample tube and the cleaning tube are moved relatively by a moving means. In a state in which the first opening portion is at the sampling position, the stored sample stored in the container flows from the first opening portion into the sample tube and flows to the second opening portion, and the stored sample can be extracted.
The sample tube and the cleaning tube are moved relatively by the moving means. In a state in which the first opening portion is at the cleaning position, the cleaning liquid is injected into the first opening portion from the cleaning tube, and the interior of the sample tube can be cleaned. At this time, the injected cleaning liquid flows out from the second opening portion. Because the cleaning liquid flows from the first opening portion to the second opening portion, the interior of the sample tube, i.e., the entire region over which the sample flows, can be cleaned.
If the cleaning liquid can flow between the first opening portion and the second opening portion, the direction of flow thereof is not particularly limited. Namely, the cleaning liquid may be injected from the second opening portion and discharged from the first opening portion.
Further, it is not only possible for the stored sample to be taken in from the first opening portion and the sample to be extracted from the second opening portion, but also, conversely, the sample may be injected from the second opening portion and added into the container from the first opening portion. In the latter case, the first opening portion does not necessarily have to communicate with the stored sample. For example, the sample may be injected and added into the container from above. Further, a state in which there is no sample in the container (i.e., the container is empty) is also possible.
By moving the sample tube and the cleaning tube relative to one another along the longitudinal direction of the sample tube, the first opening portion can be moved between the sampling position and the cleaning position. Thus, the structure for relatively moving the sample tube and the cleaning tube is simple.
Further, because the cleaning tube is provided integrally with the sample tube, as compared with a case in which the cleaning tube is provided as a member separate from the sample tube and is provided at the exterior of the sample tube, the cleaning tube can be provided and the cleaning liquid can be injected into the sample tube in a smaller space.
A second aspect of the present invention is a device for introducing an additive to a sample in a container, the device comprising: (a) a reservoir for holding an additive for introduction to a sample in a container; (b) a cleaning tube; and (c) a sample tube connected in fluid communication to the reservoir, the sample tube having an opening and being switchably mounted relative to the cleaning tube, between an adding position at which the opening of the sample tube is placed in fluid communication with the environment for introducing the additive to the sample, and a cleaning position at which the opening is placed in fluid communication with the cleaning tube for cleaning the sample tube.
When the first opening portion of the valve is at the sampling position, by supplying the additive to the second opening portion by the additive supplying device, a predetermined amount of the additive can be added to the sample.
When the cleaning liquid is supplied by the cleaning liquid supplying device at the time that the first opening portion of the valve is at the cleaning position, the cleaning liquid is injected through the cleaning tube into the interior of the sample tube and flows out from the second opening portion. In this way, the entire interior of the sample tube, i.e., the entire region over which the additive flows, can be cleaned. Accordingly, when an additive is added again after cleaning, no impurities are mixed therein, and addition can be carried out stably.
Further, the cleaning liquid supplied by the cleaning liquid supplying device is injected into the sample tube from the second opening portion, and flows out into the cleaning tube from the first opening portion which is at the cleaning position.
A third aspect of the present invention is a method of extracting a sample, comprising the steps of: (a) supplying a sample to a sample tube through a first sample tube opening; (b) discharging the sample from a second sample tube opening; (c) connecting the first sample tube opening to a cleaning tube by moving the sample tube and cleaning tube relative to one another; (d) supplying a cleaning agent to the sample tube from the cleaning tube through the first sample tube opening; and (e) contacting the sample with the first sample tube opening by moving the sample tube and cleaning tube relative to one another.
When the first opening portion of the valve is at the sampling position, by removing the stored sample from the second opening portion by the extracting device, a predetermined amount of the sample can be extracted.
Further, when the first opening portion of the valve is at the cleaning position, when the cleaning liquid is supplied by the cleaning liquid supplying device, the cleaning liquid is injected through the cleaning tube into the sample tube, and flows out from the second opening portion. In this way, the interior of the sample tube, i.e., the entire region over which the sample flows can be cleaned. Accordingly, when a sample is extracted after cleaning, air or impurities are not mixed therein, and thus, extraction can be carried out stably.
The cleaning liquid supplied by the cleaning liquid supplying device is injected into the interior of the sample tube from the second opening portion, and flows out into the cleaning tube from the first opening portion which is at the cleaning position.